Head mounted display systems have been developed for a number of different applications including use by aircraft pilots and for simulation such as virtual imaging. Head mounted displays are generally limited by their resolution and by their size and weight.
Existing displays have relatively low resolution, and because of the size and weight of available systems, these displays are positioned at the relatively large distance from the eye. Of particular importance, it is desired to keep the center of gravity of the display from extending upward and forward from the center of gravity of the head and neck of the wearer, where it will place a large torque on the wearer""s neck and may bump into other instruments during use.
There is a continuing need to present images to the wearer of a helmet mounted display in high-resolution format similar to that of a computer monitor. The display needs to be as non-intrusive as possible, leading to the need for lightweight and compact system. Existing head mounted displays have used analog cathode ray tube (xe2x80x9cCRTxe2x80x9d) devices mounted above or to the side of the user""s head which project an image onto a surface or visor mounted in front of the user""s eyes. Often these displays utilize helmets which incorporate earphones into the helmet. Other head mounted display devices have contemplated the use of liquid crystal devices that could be mounted above or to the side of the user""s head and employ reflective optics to direct an image within the field of view of the user.
In accordance with the present invention a head mounted display includes a housing in which a pair of matrix display elements are secured. These display elements are of a sufficiently light-weight and compact nature that the housing can be mounted onto the head of a user with a pair of hinge mounted arms or support elements that can be rotated relative to the housing from a closed position to an open position. When in the open position the arms extend about the opposite side of the user""s head and serve to position audio transducers mounted on the arms into proximity with the ears of the user. The arms can also be double hinged in which each arm is folded once about its mid-point and then rotated about the hinge on each side of the housing to assume the closed position. System electronics and manually adjustable controls can be positioned within the housing or the rotating arms. Positioning of the electronics and controls within the arms permits a more desirable distribution of weight evenly about the sides of the user""s head.
The inter-pupillary distance between the two displays can be adjusted such as by the use of a gear driven cam assembly mounted within the housing.
The direct view display can be a transmission type display with the light source directly adjacent the light valve active matrix and mounted within the display device. The transmission type display can, in a preferred embodiment, also receive light directly from the user""s environment so that the display overlays an image over the users existing field of view.
Alternatively, the display can be an emission type device such as an active matrix electroluminescent display or an active matrix of light emitting diodes (LEDs), or a transmissive passive matrix display.